First, the answer to Vol. 28 (last week).
I am somewhat surprised there were not more answers to this one as there are many things that can be commented on, both good and bad!
There are three primary reasons I chose this photo, the third/last of which would be much harder to recognize.
The first is that the installation technician is not properly grinding the geomembrane – in fact, with the grinder at that angle, they really have the grinder operating more like a rotary saw than a grinder and will cut too deep into the geomembrane. In this photo, it looks as if the installer is trying to bevel the geomembrane, which should have been done prior to heat-tacking the patch. In a case where the installer does this, the only fix would be to put a larger patch over the area using the proper procedures.
Second, both the patch and the parent geomembrane material appear dirty and should be cleaned prior to heat-tacking and in particular grinding.
The third is that a CQA technician is standing behind the operator, oblivious to any issues and does not have a vantage point to keep an eye on the work which he’s being paid by the owner to observe.
Other observations from the photo: the patch is circular, which means the entire weld length will be performed with uneven pressure on the extruder (vs isolated areas with rectangular patches and rounded corners); electric cords and extrusion rod are potentially a tripping hazard, so situational awareness is required (they must be somewhere); scraps of geomembrane are laying around at various places posing various hazards; the operator is wearing proper PPE other than the hardhat which was removed because it would fall off while the operator was bent over with the face shield on; the toe of slope has been ballasted; and another one you would not easily know – the green cone in the background is being used to mark areas where spark testing of the conductive geomembrane has been performed.
In these blog posts, Do You See What Glen Sees, I will present a photograph or short video related to earthwork or geosynthetics construction and have you identify the significance of what you’re seeing.
It could be things being done correctly or incorrectly. Primarily, these will be things that impact quality.
In addition to my blog, I’ll post this content on X and LinkedIn. You can post your response on one of those two.
I’ll give you my thoughts on each photo or video when I post the next installment.
Do you see what I see? Or did you find something I missed? I’m excited to find out!
